This invention relates to a method for producing a sectional view of a body, the picture elements of which are derived from the absorption of ionizing rays, preferably X- or gamma-rays in general and more particularly to an improved apparatus for carrying out such a method.
In such methods rays pass through the respective body element in the cross-sectional plane of the body in different directions. In a system of radiation receivers they are converted into electrical signals and are evaluated in an electronic storage system. Arrangements for implementing such a method, in which the body is scanned by parallel displacement of the radiation source and the radiation receiver in the cross-sectional plane of the body, are known as "scanners".
In one arrangement for implementing a method of this nature, a detector system with spatially resolving semiconductor detectors for electron beams which are released in the photocathode of an electronic vacuum image converter are used. The scintillator of the image converter is used as the receiver of the fan-shaped ray beam. In this arrangement, all the electrical signals associated with the fan-shaped beam are imaged and picked up simultaneously. Scanning the cross-sectional plane of the body by parallel displacement of the radiation source and the radiation receiver is therefore no longer necessary.
For accelerating the electrons, a solid-state image converter may be used. A vacuum image converter, in which the electrons released from a photocathode are accelerated in a vacuum section by an applied voltage of, e.g., 20 kV, is particularly well suited. The electrons then strike a detector system which contains spatially resolving detectors which are arranged in the detector system side-by-side in the cross-sectional plane of the body. The detector system contains an output line for each detector through which the output signal is fed to an electronic system. This electronic system processes the individual signals and then displays the sectional view of the body on a display screen, or the system also may contain a printer which prints out the sectional view of the body to be produced. The individual connecting leads between the detectors and the electronic system each must be brought out of the vacumm system with a feedthrough.